Variable-geometry convergent-divergent nozzles for jet propulsion engines

ABSTRACT

A primary variable-geometry convergent-divergent nozzle is controllable so that both the throat section and the exit section of the nozzle can be varied simultaneously. A first series of upstream controlled flaps of variable inclination are connected to a fixed structure, each being mounted for articulation about a hinge pin to vary the throat section of the nozzle. A second series of downstream controlled flaps of variable inclination are directly connected, respectively, to the first series of flaps and are each mounted for articulation about a hinge pin relatively to the corresponding upstream flap to vary the exit section of the nozzle. The inclinations of both series of flaps are variable by a control system which comprises, for each pair of interconnected upstream and downstream flaps, an &#39;&#39;&#39;&#39;active&#39;&#39;&#39;&#39; control element and a &#39;&#39;&#39;&#39;passive&#39;&#39;&#39;&#39; control element. The active control element is connected on the one hand to the corresponding upstream flap and on the other hand to a controllable actuating element forming part of a jack. The passive control element is connected on the one hand to the corresponding downstream flap and on the other hand to the fixed structure.

United States Patent 1191 Camboulives et al.

' JET PROPULSION ENGINES [75] Inventors: Andre Alphonse Mederic Leon Camboulives, Billancourt; Gerard Ernest Andre Jourdain, Evry; Theophile Francois Le Maout, Cesson; Roger Alfred Jules Vandenbroucke, Antony, all of France [73] Assignee: Societe Nationale dEtude et de Construction de Moteurs dAviation, Paris, France [22] Filed: Apr. 16, 1973 [21] Appl. No.: 351,578

[30 Foreign Application Priority Data Apr. 17, 1972 France ..72.13397 [52 Us. c1. 239/265.4l, 181/33 HD [51] Int. Cl. B64c 15/06, B64c 9/38 [58] Field of Search..... 239/265.l9, 265.33, 265.37,

[56] References Cited UNITED STATES PATENTS 3,024,600 3/1962 Sollinger 239/265.39 3,295,764 l/l967 Geary et al. 239/265.4l

1451 Apr. 30, 1974 FOREIGN PATENTS OR APPLICATIONS 1,174,496 12/1969 Great Britain 239/265.l9

Primary Examiner-Robert S. Ward, Jr.

[ ABSTRACT A primary variable-geometry convergent-divergent nozzle is controllable so that both the throat section and the exit section of the nozzle can be varied simultaneously. A first series of upstream controlled flaps of variable inclination are connected to a fixed structure, each being mounted for articulation about a hinge pin to vary the throat section of the nozzle. A second series of downstream controlled flaps of variable inclination are directly connected, respectively, to the first series of flaps and are each mounted for articulation about a hinge pin relatively to the corresponding upstream flap to vary the exit section of the nozzle. The inclinations of both series of flaps are variable by a control system which comprises, for each pair of interconnected upstream and downstream flaps, an active control element and a passive control element. The active control element is connected on the one hand to the corresponding upstream flap and on the other hand to a controllable actuating element forming part of a jack. The passive control element is connected on the one hand to the corresponding downstream flap and on the other hand to the fixed structure,

11 Claims, 7 Drawing Figures 1 VARIABLE-GEOMETRY CONVERGENT-DIVERGENT NOZZLES FOR JET PROPULSION ENGINES The present invention relates to a primary convergent-divergent nozzle of the kind comprising: a first set of actuated flaps, or upstream flaps, of variable inclination and each of which has an upstream portion connected to a fixed structure for articulation about a hinge pin, and a downstream portion; a second set of actuated flaps, or downstream flaps, of variable inclination and each of whichhas an upstream portion directly connected for relative articulation to the downstream portion of an upstream flap about a hinge pin, and a free downstream portion; and a control system for the inclination of said upstream and downstream flaps, so that it is possible to vary simultaneously both the throat area and the exit area of the nozzle.

The nozzle is designated more particularly for a jet propulsion engine, for example a turbojet engine, utilized to propel a flying machine, such as an aircraft.

The object of the present invention is to provide a nozzle of the kind referred to with a system, which is both simple and economical, to control the inclination of the upstream and downstream flaps, making it possible simultaneously and in accordance with a predetermined function, to adjust the throat area and the exit area of the nozzle in order to facilitate the matching of the engine to various flight conditions of the aircraft.

To this end, in accordance with the invention said control system comprises, in combination and for each pair of flaps constituted by an upstream flap and a downstream flap connected together for relative articulation, two separate control elements, namely an active" element connected on the one hand solely-to the upstream flap and, on the other hand, to a controllable actuating element, and a passive" control element connected on the one hand to the downstream flap and, on the other hand, to said fixed structure.

The controllable actuating element to which the active" control element is connected may, for example, constitute part of a jack. So far as the passive control is concerned, this may advantageously comprise a link with one end connected to the downstream flap for articulation about a hinge pin other than the common hinge pin linking upstream and downstream flaps of the same pair, and the other end connected to the fixed structure for articulation about a hinge pin other than the hinge pin connecting said upstream flap to the fixed structure.

In one embodiment of the invention, said link has a' fixed length throughout the whole of the nozzle adjustment range. In another embodiment of the invention, said link has a fixed length throughout part of the nozzle adjustment range and a variable length throughout another part of said range. To this end, the link may advantageously comprise, assembled so as to be slidable one in relation to the other, a first portion fixed to one end of the link and a second portion fixed to the other end.

In accordance with one arrangement, applicable to the latter of said embodiments, each link is associated with a stop device which stops the relative sliding movement of the said portions of the link at a certain predetermined limit. In accordance with another arrangement applicable to the same case, the mutually slidable link portions may cooperate with elastic return means which tends to reduce the total link length.

In accordance with yet another arrangement, still applicable in the aforesaid case, each pair of flaps constituted by an upstream flap and a downstream flap is associated with a stop device which stops the pivoting movement of the downstream flap in relation to the upstream flap at a predetermined angular limit. This stop device may comprise, for example, two stop elements cooperating with each other and respectively carried by the two flaps of said pair thereof.

The following description which refers to the accompanying drawings is given by way of non-limitative example and indicates how the invention may be put into effect. In the drawings:

FIG. 1 is an axial sectional view, on the line II of FIG. 2, through a convergent-divergent variablegeometry nozzle in accordance with a first embodiment of the invention; 7

FIG. 2 is an external view, in the direction of the arrow II of FIG. 1, of the nozzle shown in FIG. 1;

FIG. 3 is a transverse sectional view on the line III- III of FIG. 1 of a detail of the nozzle shown in FIG.

' FIG. 4 is a transverse sectional view on the line IV-IV of FIG. 1, through another detail of the nozzle shown in FIG. 1;

FIG. 5 is an axial sectional view, on the line V-V of FIG. 7, through a convergent-divergent variablegeometry nozzle in accordance with a second embodiment of the invention, nozzle being illustrated in one of its extreme configurations;

FIG. 6 is a view similar to that of FIG. 5, but with the nozzle illustrated in the other of its extreme configurations, and

FIG. 7 is an external view, in the direction of the arrow VII in FIG. 5, through the nozzle shown in FIG. 5.

In FIG. I, the general reference 1 is used to designate an exhaust system forming part of a jet engine designed to propel a flying machine such as an aircraft. This exhaust system is, by way of example, of the composite" or fan type, with a primary duct 2 and a secondary fairing 3.

The primary duct 2 comprises a fixed jet pipe 4 connected at the forward end to a hot gas generator (not shown), for example a gas turbine, and extending towards the rear in the form of a variable-geometry primary nozzle 5, with an exit orifice 6.

The secondary fairing 3, whose transverse section is larger than that of the primary duct 2, surrounds said primary duct and extends towards the rear beyond the exit orifice 6 of the primary nozzle. The primary duct 2 and the secondary fairing 3 define between them a secondary or by-pass duct 7.

In operation, a primary gas flow F passes through the primary nozzle 5, whilst the secondary by-pass airflow F passes through the secondary duct 7.

The present invention is concerned with the primary nozzle 5 and, more particularly, with its control. Selfevidently: the invention applies equally to cases where the primary nozzle 5 is not surrounded by a secondary fairing 3.

The jet pipe 4, at its rear end, has a flange 8 to which a flange 9 forming part of a ring 10 surrounding said jet pipe is bolted. The ring 10, at its rear portion, has spaced ribs 11 and at its front end is integral with a suspension ring 12 likewise provided with spaced ribs 13. Around the whole of the ring spaced longitudinally extending plates 14a, 14b are arranged. Each of these plates is attached, at the forward end, to the suspension ring 12 by means of a hingebolt 15 passing through the corresponding rib 13 of said ring. It is also attached, at the rear, to a yoke 16 by means of a hinge bolt 17. The yoke 16 is itself attached to the ring 10 by means of a hinge bolt 18 passing through the ribs 11 of said ring. The assembly constituted by the longitudinal plates 14a, 14b creates a fixed structure designed to carry the variable geometry nozzle 5 as well as its control.

The nozzle 5 has two sets of actuated flaps of variable incliation, namely a series of upstream actuated flaps and a set of downstream actuated flaps 30. It also comprises upstream follower flaps 40 and downstream follower flaps 50 designed, in a manner known per se, to ensure peripheral sealing of the nozzle. As FIG. 3 shows, each follower flap (in this case an upstream follower flap 40) is located between two control flaps and is applied, by the pressure of the gas flow F against the internal edges of said actuated flaps.

Each upstream actuated flap 20 is articulated, at its upstream end, to the fixed structure 14a, 14b about a hinge pin 21. An annular seal 19 provides sealing between the downstream portion of the jet pipe 4 and the upstream flaps 20 and 40.

Each downstream actuated flap is directly articulated, at its upstream end, to the downstream portion of an upstream actuated flap 20, about a hinge pin 31. Its downstream portion, which defines the exit section of the nozzle 5, is free. The follower flaps and are relatively articulated one to the other in a similar manner. In the description now following, a pair of actuated flaps, constituted by an upstream actuated flap 20 and a downstream actuated flap 30, are considered. Associated with each pair 20, 30 of actuated flaps is an improved control system which makes it possible simultaneously to vary the throat section and the exit section of the nozzle, which is the object of the present invention.

This control system comprises two separate control elements, namely an activecontrol element 22 and a passive control element 32.

The active" control element 22 is connected, at one of its ends, solely to the upstream controlled flap by a hinge pin 23. At its other end the element 22 is fixed to a controllable actuatih g e lement such as the rod of a hydraulic jack 25. The jack is articulated to the fixed structure 14a, 14b by means of stub shafts 26. The reference 27 indicates an operating fluid pipe for the jack 25.

The passive" control element 32 is constituted by a forked link of a fixed length, with a handle 32c and two branches 32a, 32b. The free end of the handle 320 of the link 32 is articulated to the downstream flap 30 about a pin 33 other than the mutual hinge pin 31 linking the upstream flap 20 and the downstream flap 30. The free end of each of the branches 32a, 32b of the link is articulated to the fixed structure 14a, 14b about a hinge pin 34 other than the pin 21 articulating the upstream flap 20 to said fixed structure.

The nozzle comprises, for example, twelve pairs of actuated flaps 20, 30, with each of which there are associated a separate jack 25 and a separate link 32. All the jacks 25 are synchronized with one another.

In operation, when the jacks 25 are supplied with pressure fluid, each of the upstream actuated flaps 20 pivots about its hinge pin 21.

In FIG. 1, the point" 31 (which is fixed in relation both to an upstream actuated flap 20 and to a downstream actuated flap 30) thus describes a circular arc whose centre is 21 and radius R Similarly the point" 33, which is fixed in relation to the control downstream actuated flap 30, describes a circular arc whose centre is 34 and with radius R These geometric data are sufficient to ensure that for every position of the upstream actuated flap 20 there is one position, and one only, for the downstream actuated flap 30. This position, in other words, is geometrically determined once it is known on the one hand the location of the axis of the pivot pin 33 on the downstream flap 30, and on the other hand the location of the axis of the pivot pin 34 on the fixed structure 14a, 14b.

It will be appreciated, therefore, that by suitably choosing the respective positions ofthe axes of the pivots 33 and 34 between which the links 32 extend, it is possible at the same time to regulate the inclination of the upstream flaps 20 in relation to the fixed structure 14a, 14b in accordance with a predetermined geometrical function; and likewise the inclination of the downstream flaps 30 in relation to the upstream flaps 20, i.e., in fact to regulate the throat section and the exit sec tion of the nozzle in order to promote matching of the jet engine to the aircraft flight conditions.

Thus, the present construction has the advantage that it makes it possible, by means ofa single set ofjacks 25, simultaneously to control the upstream flaps 20 and the downstream flaps 30 of the nozzle. This result is obtained by the use of links 32 each of which, although passive, performs the same function as an active" control element (such as a jack) with the advantages of a lower weight and lower cost, with a higher reliability.

FIGS. 5 to 7 relate to a second embodiment of the invention. In these figures, the same references have been used to indicate elements which are identical or similar to those already described with reference to FIGS. 1 to 4. In particular, there is shown the fixed structure 14a, 14b and a pair 20, 30 of actuated flaps articulated to one another about a hinge pin 31. Associated with each pair 20, 30 of actuated flaps, as before, is a control system comprising an active control element 22 (associated with a jack 25) and a passive control element which is now indicated by the reference 132.

As in the previous embodiment, the passive control element 132 is constituted by a forked link having a handle" 132C and two branches 132a, 132b. The free end of the handle 1326' of the link 132 is articulated to the downstream flap 30 about a hinge pin 33 other than the pin 32 which is responsible for linking together the upstream flap 20 and the downstream flap 30. The free end of each of the branches 132a, 132b of the link is articulated to the fixed structure 14a, 14b about a hinge pin 34 other than the pin 21 articulating the upstream flap 20 to said fixed structure.

The handle 1320 of the link 132 comprises, telescopically slidable in relation to each other, a first portion or piston 132 cx articulated to the downstream flap 30 about the hinge pin 33, and a second portion or cylinder 132cy fixed to the branches 132a, 1321: of the link.

Two stop elements 150, 151, cooperating with one another and respectively carried by the piston 132cx and by the cylinder l32cy, engage to stop the relative sliding movement of the piston and cylinder at a predetermined limit.

In addition, each pair 20, 30 of controlled flaps is associated with an angular stop device designed to stop the pivotal movement of the downstream flap 30 in relation to the upstream flap 20, at a predetermined angular limit. This angular stop device comprises two stop elements 160, 161 which cooperate with one another and which are carried respectively by the upstream flap and by the downstream flap 30.

In operation, when the upstream flaps 20 are fully open (see FIG. 5) the gas pressure (due to the flow F1) exerted upon the downstream flap tends to shorten the handle 132a of the link 132 until the stop elethe angular stop elements 160, 161 remain apart. The

position of the downstream flaps 30 is thus precisely determined.

At beginning of the closing run up the upstream flaps 20 actuated by the jacks 25, as long as the angular stop elements 160, 161 are not in contact with one another the link 132 retains a fixed length equal to its minimum length. The system controlling the inclination of the upstream flaps 20 and the downstream flaps 30 then operates in the same fashion as in the first embodiment.

As the upstream flaps 20 close, the angular stop elements 160, 161 move together until they eventually contact. The stop elements 150, 151 then disengage one another and the handle 1320 of the link 132 commences to extend. From this instant onwards, the link 132 ceases to have any effect upon the downstream flap 30 whose position, in relation to the upstream flap 20, is now solely defined by the angular stop elements 160, 161.

This second embodiment has the advantage over the first that it makes it possible to impose a variation in the ratio of exit section/throat section which is a more complex function. Accordingly, a greater degree of freedom in the choice of the locations of the hinge pins 33 and 34, to which the link 132 is articulated, is available and this makes it possible to satisfy other requirements or conditions such as that of minimum external size.

The reference 170 designates an elastic return device, such as the spring illustrated, urging the piston 132cx and the cylinder l32cy, of the handle 1320 of the link 132, in the direction of reducing total length of the link. This arrangement ensures automatic opening of the downstream flaps 30 when the nozzle 5 is inoperative.

It goes without saying that the embodiments described here are purely examples and are open to modification, in particular by the substitution of equivalent techniques without in so doing departing from the scope of the invention.

We claim:

1. A primary variable-geometry divergent nozzle comprising:

a first series of upstream actuated flaps of variable inclination, each of which has a downstream portion and an upstream portion connected for articulation about a hinge pin to a fixed structure;

convergenta second series of downstream actuated flaps of variable inclination, each of which has a free downstream portion and an upstream portion directly connected for relative articulation about a hinge pin to the downstream portion of a corresponding one of said upstream flaps; and

a system for controlling the inclination of said upstream and downstream flaps operative to vary simultaneously both the throat section and the exit section of the nozzle; which system comprises, in combination and for each pair of flaps constituted by one of said upstream flaps and the corresponding one of said downstream flaps, two separate control elements, namely an active control element connected on the one hand solely tothe upstream flap and the other hand to a controllable actuating element, and a passive control element connected on the one hand to the downstream flap and on the other hand to said fixed structure.

2. A nozzle as claimed in claim 1, wherein each controllable actuacting element, to which the active control element of the corresponding pair of flaps is connected, forms part of a jack.

3. A nozzle as claimed in claim 1, wherein each passive control element comprises a link with a first end connected to the corresponding downstream flap for articulation about a hinge pin other than that which interconnects the two flaps of the corresponding pair thereof, and a second end connected to the fixed structure for articulation about a hinge pin other than that which connects the corresponding upstream flap to said fixed structure.

4. A nozzle as claimed in claim 3, wherein said link has a fixed length throughout the whole adjustment range of the nozzle.

5. A nozzle as claimed in claim 3, wherein said link has a fixed length throughout one part of the adjustment range of the nozzle, and a variable effective length throughout another part of said range.

6. A nozzle as claimed in claim 5, wherein said link comprises, slidably mounted in relation to each other, a first portion integral with said first end of the link and a second portion integral with said' second end of the link.

7. A nozzle as claimed in claim 6, wherein each link is associated with a stop device which stops the relative sliding movement of said link portions at a predetermined limit.

8. A nozzle as claimed in claim 7, wherein said stop device comprises two stop elements cooperating one with the other and respectively carried by said portions of the link.

9. A nozzle as claimed in claim 6, wherein in each link the portions thereof slidably mounted in relation to each other cooperate with elastic return means urging said link portions in the direction of reducing total link length.

10. A nozzle as claimed in claim 5, wherein each pair of flaps constituted by an upstream flap and a downstream flap is associated with a stop device to stop the pivotal movement of the downstream flap in relation to the upstream flap at a predetermined angular limit.

11. A nozzle as claimed in claim 10, wherein said angular stop device comprises two stop elements cooperating with each other and respectively carried by the two flaps of the corresponding pair thereof. 

1. A primary variable-geometry convergent-divergent nozzle comprising: a first series of upstream actuated flaps of variable inclination, each of which has a downstream portion and an upstream portion connected for articulation about a hinge pin to a fixed structure; a second series of downstream actuated flaps of variable inclination, each of which has a free downstream portion and an upstream portion directly connected for relative articulation about a hinge pin to the downstream portion of a corresponding one of said upstream flaps; and a system for controlling the inclination of said upstream and downstream flaps operative to vary simultaneously both the throat section and the exit section of the nozzle; which system comprises, in combination and for each pair of flaps constituted by one of said upstream flaps and the corresponding one of said downstream flaps, two separate control elements, namely an ''''active'''' control element connected on the one hand solely to the upstream flap and the other hand to an adjustable drive element, and a ''''passive'''' control element connected on the one hand to the downstream flap and on the other hand to saId fixed structure.
 2. A nozzle as claimed in claim 1, wherein each adjustable actuating element, to which the active control element of the corresponding pair of flaps is connected, forms part of a jack.
 3. A nozzle as claimed in claim 1, wherein each passive control element comprises a link with a first end connected to the corresponding downstream flap for articulation about a hinge pin other than that which interconnects the two flaps of the corresponding pair thereof, and a second end connected to the fixed structure for articulation about a hinge pin other than that which connects the corresponding upstream flap to said fixed structure.
 4. A nozzle as claimed in claim 3, wherein said link has a fixed length throughout the whole adjustment range of the nozzle.
 5. A nozzle as claimed in claim 3, wherein said link has a fixed length throughout one part of the adjustment range of the nozzle, and a variable effective length throughout another part of said range.
 6. A nozzle as claimed in claim 5, wherein said link comprises, slidably mounted in relation to each other, a first portion integral with said first end of the link and a second portion integral with said second end of the link.
 7. A nozzle as claimed in claim 6, wherein each link is associated with a stop device which stops the relative sliding movement of said link portions at a predetermined limit.
 8. A nozzle as claimed in claim 7, wherein said stop device comprises two stop elements cooperating one with the other and respectively carried by said portions of the link.
 9. A nozzle as claimed in claim 6, wherein in each link the portions thereof slidably mounted in relation to each other cooperate with elastic return means urging said link portions in the direction of reducing total link length.
 10. A nozzle as claimed in claim 5, wherein each pair of flaps constituted by an upstream flap and a downstream flap is associated with a stop device to stop the pivotal movement of the downstream flap in relation to the upstream flap at a predetermined angular limit.
 11. A nozzle as claimed in claim 10, wherein said angular stop device comprises two stop elements cooperating with each other and respectively carried by the two flaps of the corresponding pair thereof. 